<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>参考链接：https://segmentfault.com/a/1190000015705604</title>
</head>
<style>
    body {

        background: #222;
    }

    .wrap {
        width: 600px;
    }

    .coupon {
        display: inline-block;
        overflow: hidden;
        border-radius: 10px;
    }

    .coupon-left {
        float: left;
        width: 150px;
        height: 150px;
        position: relative;
    }

    .coupon-left::before {
        content: '';
        position: absolute;
        top: -210px;
        display: block;
        right: -210px;
        width: 20px;
        height: 20px;
        border-radius: 50%;
        border: 200px solid orange;
        clip: rect(auto, auto, 285px, auto);
    }

    .coupon-left::after {
        content: '';
        position: absolute;
        bottom: -210px;
        display: block;
        right: -210px;
        width: 20px;
        height: 20px;
        border-radius: 50%;
        border: 200px solid orange;
        clip: rect(135px, auto, auto, auto);
    }

    .coupon-con {
        float: left;
        width: 350px;
        height: 150px;
        position: relative;
    }

    .coupon-con::before {
        content: '';
        position: absolute;
        top: -410px;
        display: block;
        left: -410px;
        width: 20px;
        height: 20px;
        border-radius: 50%;
        border: 400px solid #fff;
        clip: rect(0, auto, 485px, 410px);
    }

    .coupon-con::after {
        content: '';
        position: absolute;
        bottom: -410px;
        display: block;
        left: -410px;
        width: 20px;
        height: 20px;
        border-radius: 50%;
        border: 400px solid #fff;
        clip: rect(335px, auto, auto, 410px);
    }

    /* 2 */

    .wrap2 {
        width: 600px;
    }

    .wrap2 .coupon2 {
        display: inline-block;
        overflow: hidden;
        border-radius: 10px;
    }

    .wrap2 .coupon-left2 {
        float: left;
        width: 150px;
        height: 150px;
        position: relative;
    }

    .wrap2 .coupon-left2::before {
        content: '';
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        height: 50%;
        background: radial-gradient(circle at right top, transparent 10px, orange 10px, orange 10px)
    }

    .wrap2 .coupon-left2::after {
        content: '';
        position: absolute;
        bottom: 0;
        left: 0;
        right: 0;
        height: 50%;
        background: radial-gradient(circle at right bottom, transparent 10px, orange 10px, orange 10px)
    }

    .wrap2 .coupon-con2 {
        float: left;
        width: 350px;
        height: 150px;
        position: relative;
    }

    .wrap2 .coupon-con2::before {
        content: '';
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        height: 50%;
        background: radial-gradient(circle at left top, transparent 10px, orange 10px, #fff 10px)
    }

    .wrap2 .coupon-con2::after {
        content: '';
        position: absolute;
        bottom: 0;
        left: 0;
        right: 0;
        height: 50%;
        background: radial-gradient(circle at left bottom, transparent 10px, orange 10px, #fff 10px)
    }
</style>


<body>
    <div class="wrap">
        <div class="coupon">
            <div class="coupon-left"></div>
            <div class="coupon-con"></div>
        </div>
    </div>

    <div class="wrap2">
        <div class="coupon2">
            <div class="coupon-left2"></div>
            <div class="coupon-con2"></div>
        </div>
    </div>
</body>

</html>